We studied three typical heteromorphic leaves of Populus euphratica trees growing in the Wuhai region of Inner Mongolia,China,i.e.,lanceolate,broad-ovate and dentate broad-ovate leaves and mainly focused on the change...We studied three typical heteromorphic leaves of Populus euphratica trees growing in the Wuhai region of Inner Mongolia,China,i.e.,lanceolate,broad-ovate and dentate broad-ovate leaves and mainly focused on the changes in chlorophyll fluorescence parameters and free water and bound water content.The results show that the values of Fm（maximal fluorescence yield）,Fv/Fm（maximum photochemical quantum yield of PSII） and Fv/F0（potential quantum efficiency of PSII） of lanceolate leaves were the least on young trees,while these parameters were the least on the ovate leaves of old trees.Compared with young trees,the free water content of heteromorphic leaves of old trees increased significantly,i.e.,by 78.94% in lanceolate leaves and in the leaves of broad-ovate and dentate broad-ovate by 10.99% and 10.60%,respectively.Correlation analysis showed that free water content is significantly related to Fv/Fm and Fv/F0 in young trees,while the relationship of total water content with Fv/Fm and Fv/F0 is positive in old trees.展开更多
Water deficit is an important environmental factor restricting plant growth and photosynthesis. The effect of water deprivation on leaf water status, photosynthetic gas exchange, chlorophyll content and fluorescence p...Water deficit is an important environmental factor restricting plant growth and photosynthesis. The effect of water deprivation on leaf water status, photosynthetic gas exchange, chlorophyll content and fluorescence parameters of arta （Calligonum comosum） was studied. Five-month-old arta seedlings, grown in pots in the open air, were subjected to one of four drought treatments （i.e., mild, moderate, severe and extreme drought stress） and compared to control seedlings （normal watering regime）. Results show that leaf water potential, net photosynthesis, stomatal conductance, transpiration, photosynthetic pigment content （chlorophyll a and b） decreased with increasing levels of drought stress. Inactivation of the photosynthetic apparatus was accompanied by changes in the fluorescence characteristics, providing evidence that reduction of photosynthetic rate could be attributed to non-stomatal limitations. Alterations imply changes in photochemical conversion efficiency of photosystem II by which plants could reduce water transpiration or protect their photosynthetic apparatus from destruction. These adaptations are discussed in relation to the strategies developed to grow drought-resistant arta seedlings in desert environments.展开更多
基金supported by the National Natural Science Foundation of China (Grant No. 30671655)
文摘We studied three typical heteromorphic leaves of Populus euphratica trees growing in the Wuhai region of Inner Mongolia,China,i.e.,lanceolate,broad-ovate and dentate broad-ovate leaves and mainly focused on the changes in chlorophyll fluorescence parameters and free water and bound water content.The results show that the values of Fm（maximal fluorescence yield）,Fv/Fm（maximum photochemical quantum yield of PSII） and Fv/F0（potential quantum efficiency of PSII） of lanceolate leaves were the least on young trees,while these parameters were the least on the ovate leaves of old trees.Compared with young trees,the free water content of heteromorphic leaves of old trees increased significantly,i.e.,by 78.94% in lanceolate leaves and in the leaves of broad-ovate and dentate broad-ovate by 10.99% and 10.60%,respectively.Correlation analysis showed that free water content is significantly related to Fv/Fm and Fv/F0 in young trees,while the relationship of total water content with Fv/Fm and Fv/F0 is positive in old trees.
基金Financial support provided by the University of Kashan to carry out this work is acknowledged
文摘Water deficit is an important environmental factor restricting plant growth and photosynthesis. The effect of water deprivation on leaf water status, photosynthetic gas exchange, chlorophyll content and fluorescence parameters of arta （Calligonum comosum） was studied. Five-month-old arta seedlings, grown in pots in the open air, were subjected to one of four drought treatments （i.e., mild, moderate, severe and extreme drought stress） and compared to control seedlings （normal watering regime）. Results show that leaf water potential, net photosynthesis, stomatal conductance, transpiration, photosynthetic pigment content （chlorophyll a and b） decreased with increasing levels of drought stress. Inactivation of the photosynthetic apparatus was accompanied by changes in the fluorescence characteristics, providing evidence that reduction of photosynthetic rate could be attributed to non-stomatal limitations. Alterations imply changes in photochemical conversion efficiency of photosystem II by which plants could reduce water transpiration or protect their photosynthetic apparatus from destruction. These adaptations are discussed in relation to the strategies developed to grow drought-resistant arta seedlings in desert environments.
